An Optimized System for Interventional Magnetic Resonance Imaging-Guided Stereotactic Surgery

Abstract

Background Deep brain stimulation (DBS) electrode placement using interventional MRI has been previously reported using a commercially available skull mounted aiming device (Medtronic Nexframe MR) and native MRI scanner software. This first-generation method has technical limitations that are inherent to the hardware and software used. A novel system (SurgiVision ClearPoint) consisting of an aiming device (SMARTFrame) and software has been developed specifically for iMRI interventions including DBS. Objective A series of phantom and cadaver tests were performed to determine the system’s capability, preliminary accuracy and workflow. Methods 18 experiments using a water phantom were used to determine predictive accuracy of the software. 16 experiments using a gelatin-filled skull phantom were used to determine targeting accuracy of the aiming device. 6 procedures in three cadaver heads were performed to compare workflow and accuracy of ClearPoint with Nexframe MR. Results Software prediction experiments showed an average error of 0.9±0.5 mm in magnitude in pitch and roll (mean pitch error −0.2±0.7 mm, mean roll error +0.2±0.7 mm) and an average error of 0.7±0.3 mm in X-Y translation with a slight anterior (0.5±0.3 mm) and lateral (0.4±0.3mm) bias. Targeting accuracy experiments showed average radial error of 0.5±0.3 mm. Cadaver experiments showed a radial error of 0.2±0.1 mm with the ClearPoint system (average procedure time 88±14 minutes) vs 0.6±0.2 mm with the Nexframe MR (average procedure time 92±12 minutes). Conclusion This novel system provides the submillimetric accuracy required for stereotactic interventions including DBS placement. It also overcomes technical limitations inherent in the first-generation iMRI system.

Clinical outcomes using ClearPoint interventional MRI for deep brain stimulation lead placement in Parkinson’s disease

“…The main features of the ClearPoint system have been previously described in technical reports. 16,29 The implantable pulse generators (IPGs) and lead extenders were placed in a separate inpatient or outpatient procedure 1-3 weeks after lead implantation.…”

“…A secondgeneration device was developed (ClearPoint, MRI Interventions, Inc.) with improved mechanical controls and an integrated software package intended to improve ease of use and accuracy of targeting. 16 We recently published our experience using the ClearPoint system to implant DBS electrodes using iMRI in a series of pediatric dystonia patients with excellent outcomes. 29 In this prospective study we describe the use of the ClearPoint system to place DBS leads in adults with PD and report the clinical outcomes 12 months after surgery.…”

Parkinson’s disease outcomes after intraoperative CT-guided “asleep” deep brain stimulation in the globus pallidus internus

“…21 Interventional MRI-guided DBS offers an alternative asleep technique for direct anatomically based placement of DBS electrodes without electrophysiological mapping. 12,13,21,27 In comparison with our intraoperative CT-guided technique, performing electrode implantation in the interventional MRI suite allows for near real-time visualization of not only the lead or targeting cannula, but also the intended target. 12 This avoids the requirement for a registration scan and the associated error due to CT-MR image fusion.…”

Real-time magnetic resonance imaging-guided frameless stereotactic brain biopsy: technical note

“…Phantom and cadaveric studies using this system for deep brain stimulator lead placement have reported a mean radial error of 0.5 mm. 9 Clinical application of similar technology in 29 patients with Parkinson disease who had undergone real-time MRI-guided placement of 53 deep brain stimulation electrodes resulted in a mean radial error of 1.2 mm and a mean absolute tip error of 2.2 mm. 21 Consistent with these findings, we found a mean radial error of 1.3 mm for the final biopsy needle position and a mean absolute tip error of 1.5 mm (Table 2).…”

“…The resolution and real-time feedback of this iMRI technology has been demonstrated in phantom experiments, 12,18 nonhuman primate studies, 16,17 drug infusion cannula placement, 2 and placement of deep brain stimulator leads. 9,11,20,21 Application of this technology to stereotactic brain biopsy could eliminate misdiagnosis secondary to faulty targeting, provide realtime adaptability for needle trajectory, confirm accurate biopsy cannula position, and provide immediate imaging of complications. To determine the feasibility, accuracy, and safety of real-time MRI-guided brain biopsy, we analyzed the results in consecutive brain biopsy cases using this paradigm.…”